A method, system, and computer readable medium for managing a financial transaction of a user at a merchant, including authenticating the user via a device of the user while the user is at the merchant; transmitting activation information for activating a reusable, pre-existing, unaltered and permanent credit or debit card account number of the user from the user device to a financial institution for processing financial transactions, while the user is authenticated; submitting a payment request including the account number to the financial institution from the merchant, while the account number is activated; and de-activating the account number after the payment request is processed by the financial institution. The financial institution only accepts and processes payment requests received from merchants while the account number is activated, and the financial institution declines payment requests while the account number is de-activated.